The tangent of one of the acute angles of a right triangle is defined as the ratio between the side across the angle (opposite) and the side next to the angle (adjacent)
Considering ∠N, the side next to it is side NA, and the side across the angle is DA.
So you can express the tangent of ∠N as follows:
We know that DA=16 and NA=12, then the tangent can be calculated as:
The tangent of ∠N is 4/3